Constant versus risky choice in an eight-arm radial maze

Two groups of rats were tested in the radial arm maze to see whether variability in the amount of food with which the maze arms were baited affected their choice of arms. Half of the maze arms were baited in a constant fashion, in which each arm was baited with 3 pellets prior to each trial. The remaining arms could be baited with 0 or 6 pellets, which varied randomly across trial. Cues were added to either the constant or variable arms (depending on the rat group) in order to facilitate discrimination of the two arm sets. It was found that these cues had a significant effect on choice. Rats for which the cues corresponded to the constant arm set developed a preference for the variable arms across the course of the experiment. The results suggest that the subjects do prefer variability in the magnitude of reinforcement.